freightliner MT45 2019 - Troubleshooting Airflow; Blower Motor and Switch Issues

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2019 Amazon P80 Package Delivery Vehicle

TROUBLESHOOTING

SECTION A: AIRFLOW PROBLEMS

PROBLEM A-1, No air ow, blower does not operate

POSSIBLE CAUSE #1 - Faulty Blower Motor

CORRECTIVE ACTION - With ignition turned ON, unplug the 2-pin connector at the blower mo-

tor. Check the orange wire for +12 volts and the white wire for a fully grounded circuit. If power is

present and the circuit grounded, remove the motor and wheel from the blower housing. Inspect

for any evidence of entrapped debris or a broken blower wheel that might have prevented rotation.

If no such evidence exists, replace the blower motor.

POSSIBLE CAUSE # 2 - Blown fuse due to short in wire harness.

CORRECTIVE ACTION

- Refer to the HVAC Wiring

Diagram and the Chassis

Manufacturer's wiring infor-

mation.

Trace the entire HVAC wiring

for an electrical short.

Replace or repair as required.

POSSIBLE CAUSE #3 -

Defective Blower Switch.

CORRECTIVE ACTION -

Refer to the Blower Switch

Continuity Diagram

(Figure 1) and check the

blower switch for continuity

through the switch in all four

switch positions.

Replace the blower switch as

required.